Helminths. Includes D. immitis, the dog heartworm and D. tenuis in raccoons, D. ursi in bears, D. subdermata in porcupines, and D. repens in European dog and cat.
D. immitis: lung nodules, which can mimic pulmonary infection with eosinophilia, the others cause subcutaneous nodules, often without eosinophilia.
Cold steel i.e. cut it out.